Why are some of my command line arguments being ignored?
Blender doesn't get to read any of the arguments after -f 1, as per the manual:

Note
Arguments are executed in the order they are given!
The following command will not work, since the output and extension are set after Blender is told to render:
blender -b file.blend -a -x 1 -o //render
The following command will behave as expected:
blender -b file.blend -x 1 -o //render -a
Always position -f or -a as the last arguments.